The present invention relates to monoclonal antibodies specific for Derf II which is a major allergen of house dust mite Dermatophagoides farinae, cell lines for producing the antibodies, immunoassays in which the monoclonal antibodies are used, and purification of Derf II.
House dust is a major allergen of bronchial asthma, allergic rhinitis and the like. It is said that the allergen is caused by mites (Sakamoto, Kagaku to Seibutsu, Vol. 26, No. 2 (1988), Voorhoost, R. et al, J. Allergy, 39, 325 (1967)) and at least 90% of people who are positive in a patch test of house dust are also positive to mites (Hayakawa and Shida, Nippon Rinsho, Vol. 45, No. 8 (1987)). The mites, which are important as a cause of allergens, are Dermatophagoides farinae and Dermatophagoides pteronyssinus (T. Miyamoto et al., J. Allergy, 42, 14 (1968)). In Dermatophagoides farinae, there are two major allergens named Derf I (molecular weight 24,000) and Derf II (molecular weight 15,000-16,000). Derf I is contained in mite feces and Derf II is contained in mite bodies (and the dead bodies and their body pieces).
It is generally important to identify the original allergen in medical treatment of allergic disease. It is effective to clinically guide a patient so as to avoid the original allergen (Sakamoto, Kagaku to Seibutsu, Vol. 26, No. 2 (1988), Platts-Mills, T. A. E., J. Allergy, 83, 416-427 (1989)). Then, quantification and determination of the mite allergen in surroundings of the patient are required. Therefore, methods for detecting mite allergens in house dust have been proposed.
In these methods, a color reaction of a protein, which is derived from feces of house dust mites and extracted with alcohol, and an aromatic diazo compound (Japanese Patent Laid-open Publication Nos. 60-135844, 60-171459 and 61-59261) is not conducted by a simple process. Though the presence of a mite allergen is recognizable by the reaction, it is impossible to identify and determine the allergen. In a color reaction of body fluid of a small animal and chemicals (Japanese Patent Laid-open Publication Nos. 62-296828 and 62-296829), though the operation is simple, it is impossible to identify and determine a mite allergen because small animal allergens other than the mite allergen are detected. Further in a detection method wherein anti-serum obtained by immunizing an extract of mite bodies to an animal is used (Japanese Patent Laid-open Publication No. 63-191961), though it is possible to detect and determine living bodies of dust mites, detection and determination of the dead bodies, pieces and feces remain unexplained, and it is impossible to identify and determine the allergen.
In treatment of mite allergy, desensitization therapy is generally conducted by using a mite allergen extract. The therapy needs to determine and purify the allergen to be given (Eda, Nippon Rinsho, Vol. 44, a special number, 1986). In this regard, specificity of monoclonal antibodies which have been prepared from mammals immunized by mite bodies or feces is unknown.